Why have so many 5G phones been launched already this year?

Why are 5G phones even being unveiled already? It feels like it's barely months since 4G networks launched... so why are we even talking about selling 5G handsets already? Why did we see multiple phones being announced at MWC this year packing the new technology on board?I'm certainly not against the idea of 5G coming into the smartphone world... and wider. It's genuinely going to be a revolution. It’s going to allow multiple sensors to be connected together on a network at once &ndas